Identification, quantitation, isolation and characterization of tumor cell specific antigens are of importance in several areas of cancer research. Knowledge about these would aid cancer diagnosis, studies of the carcinogenic process, cell tranformation, and cancer immunotherapy, among others. The present study concerns the isolation, purification and immunochemistry of soluble tumor antigens of transplantable guinea pig hepatomas. BIBLIOGRAPHIC REFERENCE: Detrick-Hooks, B., Smith, H.G., Bast, R.C., Jr., Dunkel, V.C. and Borsos, T.: Naturally soluble tumor antigens from guinea pig hepatomas: Isolation and partial characterization. J. Immunol. 116: 1324-1331, 1976.